1)  (27-514)-(486-78)

    =-487-408

   =-895

2)=40

3)=407

1. \(\left(27-514\right)-\left(486-78\right)\)

\(=\left(-487\right)-408\)

\(=-895\)

2. \(\left(65-100\right)-\left(25-100\right)\)

\(=\left(-35\right)-\left(-75\right)\)

\(=40\)

3. \(\left(567-67\right)-\left(56+4+33\right)\)

\(=500-93\)

\(=407\)

\(Cau1\left(27-514\right)-\left(486-78\right)\)

\(=\left(-487\right)-408\)

\(=-895\)

\(Cau2:\left(65-100\right)-\left(25-100\right)\)

\(=-35-\left(-75\right)\)

\(=40\)

\(Cau3:\left(567-67\right)-\left(56+4+33\right)\)

\(=500-\left(60+33\right)\)

\(=500-93\)

\(=407\)

=6,5x6+4=39+4=43

=300 nka bn k mk nka 

25+30+65+100+70+10

= 25+65+10+70+30+100

= 100+100+100

= 300

LƯU Ý :SỐ 45...50,MỘT SỐ LIỀN SAU 45 

5,10,15,20,25,30,35,40,45,46,50,55,60,65,70,75,80,85,90,95,100

a ) 3,71 × 65 + 3,71 × 25 + 10 × 3,71

=\(3,17X\left(65+25+10\right)\)

=\(3,17X100\)

=\(317\)

Kim Chi Bùi , còn 2 câu nữa chạy hả ?

bài này làm như sau

(25+65)+(70+30)+(100+80)=370

a: 29+131+237+763

=160+1000

=1160

b: 65+327+15+73

=65+15+327+73

=80+400

=480

c: \(12+54:8-8\)

=12+3-8

=15-8

=7

d: \(45\cdot58+45\cdot42\)

\(=45\cdot\left(58+42\right)\)

\(=45\cdot100=4500\)

e: \(35\cdot34+35\cdot26+40\cdot35\)

\(=35\cdot\left(34+26+40\right)\)

\(=35\cdot100=3500\)

f: \(65\cdot25+65\cdot45+30\cdot65\)

\(=65\cdot\left(25+45+30\right)\)

\(=65\cdot100=6500\)

g: \(750:\left\lbrace32-\left\lbrack2^2+\left(5\cdot3^2-42\right)\right\rbrack\right\rbrace+100\)

\(=\frac{750}{32-\left\lbrack4+5\cdot9-42\right\rbrack}+100=\frac{750}{32-4-45+42}+100\)

\(=\frac{750}{28-3}+100\)

=750:25+100

=30+100

=130

h: \(\left\lbrace630:\left\lbrack16+3\cdot\left(6+3\cdot4\right)\right\rbrack\right\rbrace-1\)

\(=\frac{630}{16+3\cdot\left(6+12\right)}-1=\frac{630}{16+3\cdot18}-1\)

\(=\frac{630}{70}-1\)

=9-1=8

i: \(5871:\left\lbrack928-\left(247-82\right)\cdot5\right\rbrack+2175^0\)

\(=\frac{5871}{928-165\cdot5}+1\)

\(=\frac{5871}{928-825}+1=\frac{5871}{103}+1=57+1=58\)

k: \(375:\left\lbrace32-\left\lbrack4+\left(5\cdot3^2-42\right)\right\rbrack\right\rbrace-14\)

\(=\frac{375}{32-\left\lbrack4+5\cdot9-42\right\rbrack}-14\)

\(=\frac{375}{32-\left\lbrack4+45-42\right\rbrack}-14=\frac{375}{32-\left(4+3\right)}-14=\frac{375}{32-7}-14\)

\(=\frac{375}{25}-14\)

=15-14

=1